The total project is designed to 1) characterize in vitro the possibility that circulating aldosterone is both free and protein bound, 2) whether protein binding of aldosterone is only at low affinity to transcortin or whether there is a specific aldosterone binding protein (ABG). In vivo, we wish to study the kinetics of both aldosterone and DOC in hypertensive patients as related to (1) and conclude whether hypertensive patients have an inherited or acquired defect in aldosterone metabolism. These latter studies would involve measurements of aldosterone "binding" as well as metabolic clearance and in some situations, whole blood and plasma extraction by the liver.